Results

With demand for oil increasing and demand for refined-product storage within the midstream sector also increasing, operational reliability and uptime have become a greater priority for the owners and users of terminals and tank farms. The industry sees value in optimizing tank turnaround schedules and extending tank in-service intervals by predicting and avoiding failures while reducing the health, safety, and environmental risks associated with waste removal and human exposure. Robotic applications have developed to the point where they can help improve the reliability, safety, and costs of tank storage. Getting companies on board with robotics is not an issue, but finding the right in-service tank-inspection approaches for robotic applications is. Rengifo spoke at a panel discussion during the American Petroleum Institute Inspection and Mechanical Integrity Summit that focused on ways in which owners and users can incorporate robotics into their tank-integrity programs, as well as the obstacles they and other vendors face in facilitating robotics.

The National Institute for Occupational Safety and Health (NIOSH) and the California Department of Public Health, Occupational Health Branch, released a video to help protect oil and gas extraction workers from the hazards they face when measuring oil storage tanks. The video, Protecting Oil and Gas Workers from Hydrocarbon Gases and Vapors, weaves together a narrative of the health and safety risks involved with this activity and how employers and workers can reduce injuries and fatalities from exposure to toxic gases and oxygen-deficient atmospheres. Over 500,000 workers are employed in the oil and gas industry, a workforce that is critical to the energy infrastructure of the nation. In the video, the experiences of oil and gas workers who are responsible for measuring tank levels, or tank gauging, and the sampling of crude oil are told from the heart by a truck owner/operator, a company operations superintendent, and the widow of a man who died of sudden cardiac death while gauging. These workers often work long shifts, the weather can be severe, and many work at night or alone.

Limitations in Amine storage capacities at one of GASCO's Plants necessitates the use of temporary ISO-Storage containers to store surplus Amine during Plant / Process shutdown. This poses serious risks to equipment and personnel safety which could be categorized as a safety critical issue. This paper addresses the study carried out to resolve the issue, exploring various options and how the proposed solution mitigates the risks and ensures process safety by enhancing operational flexibility of the amine unit.

Optimization of the Plant layout for HSE constraints resulted in location of amine regeneration section farther away from the amine unit, leading to an increase of solvent inventory above design levels. As a result, during shutdown operations, the existing storage capacity was deficient by a significant margin, necessitating use of temporary facilities to overcome the shortfall.

A study was carried out to find solutions to the issue and various options were explored. Limited availability of space in an existing Plant, working within hazardous area and tie-ins with existing processes posed several challenges. The entire study was carried out utilizing GASCO's in-house resources involving full spectrum of discipline engineering expertise.

The selected option involved provision of an additional storage tank and associated facilities. This included identification of the required tank sizing and storage capacity, feasible location of tank and transfer pump, feasibility study of pipe routing and tank bund containment calculations.

As the proposed location was within the hazardous area close to live Plant units, tank installation was required to be carried out within the shutdown period. This triggered the development of a novel approach for a modular fabrication of tank, transportation in parts and installation strategy, to maximize pre-shutdown activities and enable optimum use of shutdown duration for the installation. Accordingly, study addressed this concern through extensive interaction with tank fabricator and recommended suitable methods.

Modular fabrication and installation of a new tank within live process units to ensure reliable and safe operations, is a novel approach to addressing the solvent storage issue. This approach will also avoid delays and extended shutdown duration.

The new Cosasco ER 300 Series Wireless Transmitter allows easy, affordable upgrade of storage-tank-corrosion monitors to fully automated data-collection systems. Corrosion in chemical storage tanks occurs both internally, from corrosive water gathering at the bottom of the tank, and externally, from water seeping under the tank floor. With tank farms located near suburban or environmentally sensitive areas, leakage of a tank’s contents caused by corrosion could have disastrous impact on local ecosystems. To ensure the effectiveness of anticorrosion-treatment systems, storage tanks require both internal and external corrosion monitoring. Older tank farms often have inadequate monitoring systems with no integrated data management, limiting data quality and access.

The new Cosasco ER 300 Series Wireless Transmitter allows easy, affordable upgrade of storage-tank-corrosion monitors to fully automated data-collection systems. Corrosion in chemical storage tanks occurs both internally, from corrosive water gathering at the bottom of the tank, and externally, from water seeping under the tank floor. With tank farms located near suburban or environmentally sensitive areas, leakage of a tank’s contents caused by corrosion could have disastrous impact on local ecosystems. To ensure the effectiveness of anticorrosion-treatment systems, storage tanks require both internal and external corrosion monitoring. Older tank farms often have inadequate monitoring systems with no integrated data management, limiting data quality and access.

Innumerable above ground storage tanks in hydrocarbon process plants, which are located in aggressive soil at coastal areas, are at a risk from bottom plate corrosion, due to formation of a galvanic corrosion cell between the tank bottom plate and the soil. This galvanic corrosion cell formation effect is more predominant if the content of the tank is stored at a high temperature. At such situations traditional methods of passive barrier protection systems such as Sand-bitumen tank foundation pad or soil side Paint/coating of the bottom plates cannot prevent corrosion. Tank leakage due to corrosion poses significant threat for the safety of the plant equipments and personnel due to possibility of occurrence of the fire hazards, if the tank content is hazardous material. The replacement of bottom plate due to corrosion damage is also found to be costly. Suitably designed Cathodic Protection system using either close or remote anode ground bed supplemented with soil side Paint/coating of bottom plate is the appropriate protective measure to ensure the integrity of the tank bottom plates against soil side corrosion for a longer period. On application of Cathodic Protection system, it generates a counter cell to nullify the effects of the naturally occurring galvanic corrosion cell, thereby stop the corrosion activity entirely as it arrests the basic cause of corrosion itself. Adequate awareness is still not available uniformly across the globe regarding application of CP System for soil side corrosion prevention of above ground storage tank bottom plates

INTRODUCTION

Storage tanks normally receive little attention may be because of the reason that their utility are not directly related with the day-to-day production or plant operation. These reasons might have led many tank owners to adopt a preventive maintenance approach rather than providing a proactive maintenance strategy such as application of CP System. Also many people especially in the developing countries put forward their argument against application of CP System for above ground storage tanks by saying "Since no corrosion problem was observed for the tanks without CP System for last so many years, where from the need for CP System arises now", Sometimes such arguments are also hard even if the tanks are located at aggressive soil conditions of coastal areas, this indicates the mind set of certain people to take chance on the safety aspects rather than adopting the new developments of the CP System technology to their advantages to ensure the safety. The operating experience demonstrates that the consequences of leaks in tanks could be hazardous and environmental threatening if the tanks contain flammable material such as hydrocarbon. The leak repair or bottom plate replacement has been cumbersome and may be costly affair in certain cases if unplanned shutdown can not be avoided for this purpose. The experience indicates the cost of CP System application is within 10% of the bottom plate replacement cost. Therefore, it is worth investing on the CP System rather than taking any chance on the safety of the plant, equipment, personnel and environment. This paper brings into focus the various cause of corrosion and threats due to corrosion in storage tanks operating in the coastal area, aggressive soil and high temperature environment.